Gamma Capricorni

Gamma Capricorni (γ Capricorni, abbreviated Gamma Cap, γ Cap), named Nashira /ˈnæʃɪrə/,[10] is a giant star in the constellation of Capricornus. Based on parallax measurements obtained during the Hipparcos mission, it is about 139 light-years from the Sun. It is 2.56 degrees south of the ecliptic, so it can be occulted by the Moon, and (rarely) by planets.

γ Capricorni
Location of γ Capricorni (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Capricornus
Right ascension 21h 40m 05.4563s[1]
Declination −16° 39′ 44.308″[1]
Apparent magnitude (V) +3.67[2]
Characteristics
Spectral type kF0hF1VmF2[3]
U−B color index +0.22[4]
B−V color index +0.32[4]
Variable type α2 CVn[5]
Astrometry
Radial velocity (Rv)−31.2[6] km/s
Proper motion (μ) RA: 187.39[1] mas/yr
Dec.: −22.33[1] mas/yr
Parallax (π)23.48 ± 1.10[1] mas
Distance139 ± 7 ly
(43 ± 2 pc)
Absolute magnitude (MV)+2.60[7]
Details
Surface gravity (log g)3.95[8] cgs
Temperature7,520[8] K
Metallicity [Fe/H]+0.5[8] dex
Rotational velocity (v sin i)40[9] km/s
Other designations
Nashira, 40 Capricorni, HR 8278, HD 206088, NN 4209, BD−17°6340, FK5 812, HIP 106985, SAO 164560
Database references
SIMBADdata

Nomenclature

γ Capricorni (Latinised to Gamma Capricorni) is the star's Bayer designation.

It bore the traditional name Nashira, derived from the Arabic سعد ناشرة sa'd nashirah "the lucky one" or "bearer of good news". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[11] to catalogue and standardize proper names for stars. The WGSN approved the name Nashira for this star on 21 August 2016 and it is now so included in the List of IAU-approved Star Names.[10]

In Chinese, 壘壁陣 (Lěi Bì Zhèn), meaning Line of Ramparts, refers to an asterism consisting of Gamma Capricorni, Kappa Capricorni, Epsilon Capricorni, Delta Capricorni, Iota Aquarii, Sigma Aquarii, Lambda Aquarii, Phi Aquarii, 27 Piscium, 29 Piscium, 33 Piscium and 30 Piscium.[12] Consequently, the Chinese name for Gamma Capricorni itself is 壘壁陣三 (Lěi Bì Zhèn sān, English: the Third Star of Line of Ramparts).[13]

Namesake

Nashira (AK-85) was a United States Navy ship, though it was never commissioned and never bore the USS designation.[14][15]

Properties

γ Capricorni is a hot chemically peculiar Am star with a mean apparent magnitude of +3.67. It is classified as an α2 Canum Venaticorum type variable star and its brightness varies by 0.03 magnitudes.[5]

References
  1. Perryman, M. A. C.; et al. (July 1997). "The HIPPARCOS Catalogue". Astronomy & Astrophysics. 323: L49–L52. Bibcode:1997A&A...323L..49P.
  2. Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  3. Abt, Helmut A.; Morrell, Nidia I. (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". Astrophysical Journal Supplement. 99: 135. Bibcode:1995ApJS...99..135A. doi:10.1086/192182.
  4. Johnson, H. L.; Iriarte, B.; Mitchell, R. I.; Wisniewskj, W. Z. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory. 4 (99): 99. Bibcode:1966CoLPL...4...99J.
  5. Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  6. Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication. Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W.
  7. Eggen, Olin J. (July 1998), "The Age Range of Hyades Stars", The Astronomical Journal, 116 (1): 284–292, Bibcode:1998AJ....116..284E, doi:10.1086/300413.
  8. Burkhart, C.; Coupry, M. F. (September 1991). "The A and Am-Fm stars. I - The abundances of Li, Al, Si, and Fe". Astronomy and Astrophysics. 249 (1): 205–216. Bibcode:1991A&A...249..205B.
  9. Royer, F.; Grenier, S.; Baylac, M.-O.; Gómez, A. E.; Zorec, J. (October 2002). "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i". Astronomy and Astrophysics. 393 (3): 897–911. arXiv:astro-ph/0205255. Bibcode:2002A&A...393..897R. doi:10.1051/0004-6361:20020943. S2CID 14070763.
  10. "Naming Stars". IAU.org. Retrieved 7 March 2018.
  11. IAU Working Group on Star Names (WGSN), International Astronomical Union, retrieved 22 May 2016.
  12. (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  13. (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived January 30, 2011, at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  14. "Ship Naming in the United States Navy". Naval History & Heritage Command. Archived from the original on 3 January 2015.
  15. "NavSource Online: Service Ship Photo Archive: AK-85 Nashira". navsource.org. Retrieved 28 December 2016.
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